Sensor for measuring blade tip clearance in gas turbines

Determining a distance between stationary and moving portions of a turbo machine including generating, by a fixed gap capacitive probe, a first output signal based on a characteristic of a gas in a gas flow path of the turbo machine, wherein the fixed gap capacitive probe is located in the stationary portion and is configured to sense a characteristic of a gas flowing through the gas flow path. Also, a variable gap capacitive probe, located adjacent the fixed gap capacitive probe, is used to generate a second output signal based on a distance between the variable gap capacitive probe and the moving portion, wherein the variable gap probe is configured to capacitively couple to the moving portion of the turbo machine. Afterwards, the value of the second output signal can be adjusted based on the first output signal to produce an adjusted output signal.